What time does your reception start and how long is it?

Right now I'm working on restructing my reception time due to a last minute change and I was wondering what time does the typical reception start and how long it goes on for? Originally I had my venue time set to end at midnight...but due to a change I have to change up the timeline. I'm wondering if 10pm or 10:30pm is too early for a reception to end or if I should somehow see if more time is possible to add on but then would adding time on make the reception go on for an unessarily long time? Thanks for any info!